The embodiments described herein relate generally to an electric machine and, more particularly, to a stator assembly included within the electric machine that includes an insulation member for insulating stator laminations.
In at least some known salient-pole-type electrical machines, a stator core is formed from stator laminations. Magnet wire is wound around portions of the stator core to form stator windings. Insulation members may be used to insulate end turns of the magnet wire from an electric ground. At least some known stator laminations are formed by punching a linear strip of stator teeth from a sheet of stock material. The stator laminations are stacked to form a plurality of stator segments, and the insulation members are positioned such that magnet wire may be wound about the stator segments. The insulation members are configured to provide electrical insulation between the stator laminations and the magnet wire windings.
In at least one known stator assembly, the stator core includes openings configured to receive features included in the end cap. The features are used to secure the end caps to the stator core such that the end caps are properly aligned with stator core teeth. However, the openings in the stator core causes undesirable electromagnetic characteristics.
In at least another known stator assembly, each end cap includes a post or hook that protrudes away from the end cap. A tie-down winds between adjacent stator segments and engages with the hooks of adjacent end caps to hold the adjacent stator segments together during assembly. However, using a tie-down to engage posts of adjacent stator segments does not insulate the stator core from the magnet wire.
In yet another known stator assembly, a piece of plastic insulation is positioned within the slot of a corresponding stator segment. An end cap is positioned around both an end face of the stator core and the plastic insulation such that the plastic insulation is secured to the core. Generally, in these known stator assemblies, the plastic insulation has a thickness that extends into the slot between adjacent stator segments. Furthermore, the end cap in these known embodiments must extend into the slot to secure the plastic insulation to the core. As such, the slot volume available for magnet wire may be significantly reduced. The reduction in slot volume caused by the thick plastic insulation and the width of the end cap may result in an undesirable copper/air ratio. For example, the cooper/air ratio of such known stator assemblies may be approximately 35%.